GROWTH OF THE CEREBRAL CORTEX Dol 
density in underfed brains weighing less than 1.0 gram is on the 
_ average 17 per cent, and that in underfed brains weighing more 
than 1.0 gram is almost equal to the standard for the same age. 
As in the underfed brains weighing less than 1.0 gram, the relative 
volume of the cortex-is smaller than in the standard, it follows 
that the underfed brains, if they contain the same number of cells, 
must have a relatively higher cell density in a unit volume to 
balance the smaller total volume of the cortex. 
8. The relative value of the computed number of the nerve 
cells in the entire cortex, calculated by the formula N x L.F x 
W.D x T, in the underfed was compared with the corresponding 
standard value for the same age and the former was found to be 
only slightly higher than the latter, so that they may be regarded 
as practically the same. If so, the process of the cell division 
in the cerebrum must have progressed according to the advancing 
age, in spite of the starvation. 
9. The size of the nerve cells was studied on the pyramids in the 
lamina pyramidalis and on the ganglion cells in the lamina gang- 
lionaris. The cell body of the pyramids in the underfed brains 
weighing less than 1.0 gram is smaller by 11.2 per cent in average 
diameter and that in brains weighing more than 1.0 gram smaller 
by 8.3 per cent than the standards for the same age. The corre- 
sponding figures for the nuclei of the pyramids are 15.3 per cent 
and 11.0 per cent. 
The cell body of the ganglion cells in the underfed brains 
weighing less than 1.0 gram is smaller in average diameter by 
11.8 per cent, and that in the underfed brains weighing more than 
1.0 gram is smaller by 3.1 per cent than the standards for the 
same age. The corresponding values for the nuclei of the gang- 
lion cells are less by 12.5 per cent and 5.1 per cent, respectively. 
So, on the average, the nerve cells in the cortex of the underfed of 
all weights are smaller in average diameter by about 9 per cent 
(for the underfed brains weighing less than 1.0 gram by about 
12 per cent and for those weighing more than 1.0 gram only 
by about 6 per cent), and consequently smaller in volume by 
about 25 per cent than the standard cells of the same age. These 
determinations apply only to the largest cells found at the 
measured locality. 
